摘要
- 条件指令
- 循环指令
- 评论案例
- 实例成员之computed
- 实例成员之watch
- 分隔符
- 组件：局部组件和全局组件
- 局部组件与全局组件之间信息传输
一、条件指令扩展
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<style>li {list-style: none;}</style>
</head>
<body>
<div id="app">
<ul>
<li @click="action('a')"><button>a</button></li>
<li @click="action('b')"><button>b</button></li>
<li @click="action('c')"><button>c</button></li>
</ul>
<ul>
<li v-if="flag=='a'">aaaaaa</li>
<li v-if="flag=='b'">bbbbbb</li>
<li v-if="flag=='c'">cccccc</li>
</ul>
</div> <script src="vue.js"></script>
<script>
new Vue({
el: '#app',
data: {
flag: 'a'
},
methods:{
action:function (s) {
this.flag = s
}
}
})
</script>
</body>
</html>
二、循环指令v-for=“num in nums”
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<style>li {list-style: none}</style>
</head>
<body>
<div id="app">
<ul>
<li v-for="addr in addrs">{{ addr }}</li>
</ul>
<ul>
<li v-for="(addr, index) in addrs">{{ index }}.{{ addr }}</li>
</ul>
<ul>
<li v-for="info in user">{{ info }}</li>
</ul>
<ul>
<li v-for="(v, k, index) in user">{{ index }}.{{ k }}={{ v }}</li>
</ul>
</div>
<script src="vue.js"></script>
<script>new Vue({
el: '#app',
data: {
addrs: ['北京','上海','深圳','武汉'],
user: {'name':'Sgt', 'age': 18, 'gender': 'male'}
} }) </script>
</body>
</html>
显示结果：
三、评论示例：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
<style>
li {list-style: none;}
span {
cursor: pointer;
color: red;
}
</style>
</head>
<body>
<div id="app">
<input type="text" v-model="val">
<button @click="commenting">评论</button>
<hr>
<ul>
<li v-for="(comment, index) in comments">
#{{index}}楼 {{comment}}
<span @click="comment_del(index)">x</span>
</li>
</ul>
</div>
<script>new Vue({
el: '#app',
data: {
val: '',
comments: []
},
// splice: 从哪个索引开始 操作的位数 操作成的结果(可变长)
methods: {
commenting:function () {
let newComment = this.val;
this.comments.splice(0,0,newComment);
this.val = ''
},
comment_del: function (index) {
this.comments.splice(index,1)
}
}
})
</script>
</body>
</html>
四、实例成员computed
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<p>
姓：<input type="text" v-model="first_name">
名：<input type="text" v-model="last_name">
</p>
<p>
姓名：<b>{{full_name}}</b>
</p>
</div>
<script>
new Vue({
el: '#app',
data: {
first_name:'',
last_name:'',
},
computed: {
// 1.在computed中定义的变量的值等于绑定的函数的返回值
// 2.绑定的函数中出现的所有vue变量都会被监听
full_name:function () {
return this.first_name + this.last_name
}
}
})
</script>
</body>
</html>
五、实例成员watch
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<p>
<input type="text" v-model="full_name">
</p>
<p>
姓：<b>{{first_name}}</b>
名：<b>{{last_name}}</b>
</p>
</div>
<script>
new Vue({
el: '#app',
data: {
full_name: '',
first_name: '',
last_name: ''
},
watch: {
// watch会监听data的变量，当watch里指定的变量发生改变，函数被调用
full_name:function () {
this.first_name = this.full_name.slice(0,1);
this.last_name = this.full_name.slice(1)
}
}
})
</script>
</body>
</html>
六、分隔符：自定义Vue插值表达式
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<p>{{ msg }}</p>
<p>{{{ msg }}</p>
<p>${ msg }$</p>
</div>
<script>
new Vue({
el:'#app',
data:{msg: 'Hello Vue!'},
delimiters: ['${','}$']
})
</script>
</body>
</html>
七、局部组件与全局组件
①组件的概念：
组件：是有html模板，有css样式，有js逻辑的集合体
根组件的模板就是使用挂载点，子组件必须自己定义template
示例：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<h1>组件概念</h1>
</div>
<script>
new Vue({
el: '#app',
template:`
<div>
<h1 style="color: red;">组件渲染的模板</h1>
<h2 @click="action">副标题</h2>
</div>`,
data: { },
methods: {
action:function () {
alert('123')
}
}
})
</script>
</body>
</html>
②局部组件：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>局部组件</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<abc></abc>
<abc></abc>
</div>
<script>
// 开始定义局部组件
let localTag= {
//data要实现组件的复用，需要为每个组件提供一个名称空间(作用域)
//data值就是一个存放数据的字典
//所以data值在局部组件中被定义为一个可以产生名称空间的函数的返回值(字典)
data:function () {
return {
count: 0,
}
},
template:`
<div style="border: solid;width: 100px">
<h1>标题</h1>
<p class="c1">文本内容</p>
<p class="c2" @click="action"><button>被点击{{count}}次</button></p>
</div>
`,
methods:{
action:function () {
this.count++
}
}
}; new Vue({
el:'#app',
data:{ },
// 局部组件必须要注册
components: {
'abc': localTag
}
})
</script>
</body>
</html>
分析：
③全局组件：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>全局组件</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app"> </div>
<script>
// 开始定义全局组件
// Vue.component(组件名, {组件主体});
Vue.component('keepOn',{
data:function () {
return {
count: 0,
}
},
template:`
<div style="border: solid;width: 100px">
<h1>标题</h1>
<p class="c1">文本内容</p>
<p class="c2" @click="action"><button>被点击{{count}}次</button></p>
</div>
`,
methods:{
action:function () {
this.count++
}
}
});
// 全局组件无需再跟组件中注册
new Vue({
el:'#app',
data:{ },
})
</script>
</body>
</html>
全局组件与局部组件大部分地方都是一样定义的，区别在于：
全局组件定义时候使用：(且无需再跟组件处注册)
Vue.component(组件名, {组件主体});而局部组件则使用：
let localTag={组件主体}而且需要在根组件内注册：component:{'abc':localTag},这里的abc为自己定义的组件名，localTag也是自己声明的一个变量名，都可以自己随便起。
八、局部组件和全局组件数据的传递
父传子
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>父传子</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<local-tag :xxx="msg"></local-tag> </div>
<script>
let localTag = {
// 子组件拿自定义属性
props:['xxx'],
template:`
<div>
<h1>信息</h1>
<p>{{ xxx }}</p>
</div>
`
};
new Vue({
el:'#app',
data:{
msg: '我是根组件的数据'
},
components: {
// 'localTag':localTag,
// localTag:localTag,
localTag
}
})
</script>
</body>
</html>
子传父
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>子传父</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
<script src="vue.js"></script>
</head>
<body>
<div id="app">
<h1>{{title}}</h1>
<global-tag @recv="get_title"></global-tag> </div>
<script>
Vue.component('global-tag',{
template:`
<div>
<input type="text" v-model="msg">
</div>
`,
data: function () {
return {
msg:''
}
},
methods:{},
watch: {
msg: function () {
this.$emit('recv', this.msg)
}
}
});
new Vue({
el:'#app',
data:{
title: '根组件的标题'
},
methods: {
get_title:function (msg) {
this.title=msg
}
} }) </script>
</body>
</html>